The mounting of a gas turbine engine to an aircraft structure may include the use of multiple pins, or dowels that project from the aircraft structure. The engine is hoisted or positioned so that the pins are inserted into matching sockets in an engine housing. Adjacent the sockets and pins are mount pads, flat bosses or lands with internally threaded blind holes to receive fastening bolts that secure the engine to the aircraft structure.
A turbo-prop gas turbine engine includes a reduction gearbox housing that is a relatively large and robust component making the housing suitable for mounting the engine to the aircraft. To reduce engine weight, the gearbox housing is often cast from magnesium alloy which has a relatively high strength to weight ratio and high temperature strength.
The pins are typically made of steel and coatings, paint and sealing compounds can be partially effective in protecting the socket from electro-galvanic corrosion due to the dissimilar metals. However such coatings are subject to wear and since engines are sometimes removed and reinstalled during maintenance activities, the integrity of the coatings can be compromised. Fretting and corrosion can still occur within the sockets since they can be exposed to moisture, salt and abrasive dust particles in operation and during maintenance. Improvement is desirable.